'Throbbing' sound at 100 Km/Hr plus - 2008 Pajero GLS

[KaiV]

Hi all

I doubt its an of the above - my experience is as follows

Had this about 2 years ago. Prop shafts were balanced, replaced and re balanced to no avail
Diff bushes replaced - slight betterment
Paj spent near 3 weeks with Mitsubishi technical - they could not really find a problem at all
Tires changed - problems gone
- On tires, i have found the likes of Pirelli and Hankooks (softer type tires) make it worse, harder tires like the BFG make it better but in saying that, i think that they just masked the problem

Have your differential checked. My Gen 4 - 2008 has totally failed. Gears are fine, but the LHS bearing has collapsed. She still drives like a dream, albeit that she has around 13mm play in the side-shaft and the humming noise from over 100

This does not happen overnight and with daily use, this just gets worse n worse. (getting replacement diff n side-shaft on Monday )

Further, this cannot be measured if the Paj is on the lift with its feet hanging in the air. She needs to stand on the tires on a lift - take her up_ and see if there is any vertical play in the side-shafts. In my experience, humming is from a failing bearing.

[Tony M]

Thanks KaiV,

I'll take a look under the vehicle and see if I can move the diff side shafts myself (don't have access to a lift).

The source of the noise is still a mystery (latest took it to exhaust specialist to check the exhaust - no problems found) and 'seems' to be coming from the front left.
I'm now suspecting it might be engine related due to the 'pulsing' nature.
The Rev counter doesn't show any pulsing but I guess it's electronic and wont show any short term changes (probably has an integration capacitor set-up) unlike the older vehicles with a mechanical speedo cable.
So it might be something to do with the fuel feed (pump through to injectors) or associated sensors.
It might also be something simple like the vacuum hoses having a leak somewhere but I find it difficult to trace the vacuum side (can't find a diagram of the 'vacuum system' per se).

Anybody any suggestions of who in the Western Cape can check the diesel fuel side out professionally?

Regards to all,
Tony